//
// Copyright (C) 2024 EA group inc.
// Author: Jeff.li lijippy@163.com
// All rights reserved.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
//
//


#include <turbo/container/small_vector.h>
#include <turbo/memory/mem_alloc.h>
#include <turbo/base/internal/raw_logging.h>
#include <cstdint>

namespace turbo {

// Check that no bytes are wasted and everything is well-aligned.
    namespace {
// These structures may cause binary compat warnings on AIX. Suppress the
// warning since we are only using these types for the static assertions below.
#if defined(_AIX)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Waix-compat"
#endif
        struct Struct16B {
            alignas(16) void *X;
        };
        struct Struct32B {
            alignas(32) void *X;
        };
#if defined(_AIX)
#pragma GCC diagnostic pop
#endif
    }
    static_assert(sizeof(SmallVector < void * , 0 >) ==
                  sizeof(unsigned) * 2 + sizeof(void *),
                  "wasted space in SmallVector size 0");
    static_assert(alignof(SmallVector < Struct16B, 0 >) >= alignof(Struct16B),
                  "wrong alignment for 16-byte aligned T");
    static_assert(alignof(SmallVector < Struct32B, 0 >) >= alignof(Struct32B),
                  "wrong alignment for 32-byte aligned T");
    static_assert(sizeof(SmallVector < Struct16B, 0 >) >= alignof(Struct16B),
                  "missing padding for 16-byte aligned T");
    static_assert(sizeof(SmallVector < Struct32B, 0 >) >= alignof(Struct32B),
                  "missing padding for 32-byte aligned T");
    static_assert(sizeof(SmallVector < void * , 1 >) ==
                  sizeof(unsigned) * 2 + sizeof(void *) * 2,
                  "wasted space in SmallVector size 1");

    static_assert(sizeof(SmallVector < char, 0 >) ==
                  sizeof(void *) * 2 + sizeof(void *),
                  "1 byte elements have word-sized type for size and capacity");

/// Report that MinSize doesn't fit into this vector's size type. Throws
/// std::length_error or calls report_fatal_error.
    [[noreturn]] static void report_size_overflow(size_t MinSize, size_t MaxSize);

    static void report_size_overflow(size_t MinSize, size_t MaxSize) {
        std::string Reason = "SmallVector unable to grow. Requested capacity (" +
                             std::to_string(MinSize) +
                             ") is larger than maximum value for size type (" +
                             std::to_string(MaxSize) + ")";
        TURBO_RAW_LOG(FATAL, Reason.c_str());
    }

    /// Report that this vector is already at maximum capacity. Throws
    /// std::length_error or calls report_fatal_error.
    [[noreturn]] static void report_at_maximum_capacity(size_t MaxSize);

    static void report_at_maximum_capacity(size_t MaxSize) {
        std::string Reason =
                "SmallVector capacity unable to grow. Already at maximum size " +
                std::to_string(MaxSize);
        TURBO_RAW_LOG(FATAL, Reason.c_str());
    }

    // Note: Moving this function into the header may cause performance regression.
    template<class Size_T>
    static size_t getNewCapacity(size_t MinSize, size_t TSize, size_t OldCapacity) {
        constexpr size_t MaxSize = std::numeric_limits<Size_T>::max();

        // Ensure we can fit the new capacity.
        // This is only going to be applicable when the capacity is 32 bit.
        if (MinSize > MaxSize)
            report_size_overflow(MinSize, MaxSize);

        // Ensure we can meet the guarantee of space for at least one more element.
        // The above check alone will not catch the case where grow is called with a
        // default MinSize of 0, but the current capacity cannot be increased.
        // This is only going to be applicable when the capacity is 32 bit.
        if (OldCapacity == MaxSize)
            report_at_maximum_capacity(MaxSize);

        // In theory 2*capacity can overflow if the capacity is 64 bit, but the
        // original capacity would never be large enough for this to be a problem.
        size_t NewCapacity = 2 * OldCapacity + 1; // Always grow.
        return std::clamp(NewCapacity, MinSize, MaxSize);
    }

    template<class Size_T>
    void *SmallVectorBase<Size_T>::replaceAllocation(void *NewElts, size_t TSize,
                                                     size_t NewCapacity,
                                                     size_t VSize) {
        void *NewEltsReplace = turbo::safe_malloc(NewCapacity * TSize);
        if (VSize)
            memcpy(NewEltsReplace, NewElts, VSize * TSize);
        free(NewElts);
        return NewEltsReplace;
    }

// Note: Moving this function into the header may cause performance regression.
    template<class Size_T>
    void *SmallVectorBase<Size_T>::mallocForGrow(void *FirstEl, size_t MinSize,
                                                 size_t TSize,
                                                 size_t &NewCapacity) {
        NewCapacity = getNewCapacity<Size_T>(MinSize, TSize, this->capacity());
        // Even if capacity is not 0 now, if the vector was originally created with
        // capacity 0, it's possible for the malloc to return FirstEl.
        void *NewElts = turbo::safe_malloc(NewCapacity * TSize);
        if (NewElts == FirstEl)
            NewElts = replaceAllocation(NewElts, TSize, NewCapacity);
        return NewElts;
    }

    // Note: Moving this function into the header may cause performance regression.
    template<class Size_T>
    void SmallVectorBase<Size_T>::grow_pod(void *FirstEl, size_t MinSize,
                                           size_t TSize) {
        size_t NewCapacity = getNewCapacity<Size_T>(MinSize, TSize, this->capacity());
        void *NewElts;
        if (BeginX == FirstEl) {
            NewElts = turbo::safe_malloc(NewCapacity * TSize);
            if (NewElts == FirstEl)
                NewElts = replaceAllocation(NewElts, TSize, NewCapacity);

            // Copy the elements over.  No need to run dtors on PODs.
            memcpy(NewElts, this->BeginX, size() * TSize);
        } else {
            // If this wasn't grown from the inline copy, grow the allocated space.
            NewElts = turbo::safe_realloc(this->BeginX, NewCapacity * TSize);
            if (NewElts == FirstEl)
                NewElts = replaceAllocation(NewElts, TSize, NewCapacity, size());
        }

        this->BeginX = NewElts;
        this->Capacity = NewCapacity;
    }

    template
    class turbo::SmallVectorBase<uint32_t>;

// Disable the uint64_t instantiation for 32-bit builds.
// Both uint32_t and uint64_t instantiations are needed for 64-bit builds.
// This instantiation will never be used in 32-bit builds, and will cause
// warnings when sizeof(Size_T) > sizeof(size_t).
#if SIZE_MAX > UINT32_MAX

    template
    class SmallVectorBase<uint64_t>;

// Assertions to ensure this #if stays in sync with SmallVectorSizeType.
    static_assert(sizeof(SmallVectorSizeType < char > ) == sizeof(uint64_t),
                  "Expected SmallVectorBase<uint64_t> variant to be in use.");
#else
    static_assert(sizeof(SmallVectorSizeType<char>) == sizeof(uint32_t),
                  "Expected SmallVectorBase<uint32_t> variant to be in use.");
#endif
} // namespace turbo